The bupe ceiling is high enough for heaps of people. I would say for the majority of opiate addicts in Australia, it would be sufficient (yes, I'm guessing)
Even people using tons of good heroin, or hundreds of milligrams of oxycodone multiple times a day have been able to transition to bupe easily, without even having to use the maximum dose. That doesn't mean it's for everyone, but I think it's far more effective than you think.
Benefits of bupe -
Less fatigue than methadone.
Doesn't seem as hard on the body (I don't have any links to back that up)
Blocks receptors so if you want to use, you'll likely have to wait three days for the bupe to clear.
Gave me energy when I had my dose in the morning. Other people have noticed this also. (more so than methadone)
It's further away in it's actions from regular opiates, whereas methadone is a full agonist like heroin/morphine/oxy
It's believed to be easier to come off (this hasn't really been proven yet I don't think)
Overdose is almost a non-issue.
In some countries you can get a month of take aways at once. (like in the US, however....it costs much more than methadone there)
I'm sure I could think of more but just got off a night shift and my brain is a bit slow

I'm sure others will list some other benefits.
For people that aren't set on giving up opiates, maybe bupe isn't as effective. If you still want to get high, than methadone is a pretty good option...and once you're on a decent dose of methadone is can be almost impossible for some people to switch to bupe.
Crankinit: "Plenty of people" are still a very small minority. Any substance with a metabolic ceiling will always have only limited value.
Technically true but I think you'd have to be a doctor treating lots of patients with bupe to get a good idea of who it works for it, and who it doesn't. Maybe looking at rates of bupe vs. methadone patients in the last few years would give a better idea of whether it's a very small minority of opiate dependant people or a larger amount.